Bound the typed-structure dictionary with maxOwnStructures

index.js

@@ -38,6 +38,11 @@ export function createStructon(BaseClass) {
 		constructor(options = {}) {
 			super(options);
 
+			// Honor maxOwnStructures for the typed-struct path: bounds the per-encoder typed-structure
+			// dictionary (+ transition trie). Once reached, novel shapes fall back to plain encoding
+			// instead of growing the dictionary without limit. Default: uncapped (no behavior change).
+			if (options?.maxOwnStructures != null) this.maxOwnStructures = options.maxOwnStructures;
+
 			// Initialise typed structures state on this instance
 			if (!this.typedStructs) this.typedStructs = [];
 
@@ -75,6 +80,13 @@ export function createStructon(BaseClass) {
 						}
 						return encoded;
 					}
+					// Capped miss: fall back to plain base encoding. The base may persist its own
+					// named structures via saveStructures, overwriting our combined {named, typed}
+					// payload and stranding previously written struct data. Re-save afterward so the
+					// typed structures survive (this.structures now also holds any base record added).
+					const result = superEncode(value, encodeOptions);
+					if (this.typedStructs && this.typedStructs.length > 0) this._saveTypedStructures();
+					return result;
 				} finally {
 					this._onStructureAdded = null;
 				}